Fuel Injector Nozzle Shield Composite Thermal Protection

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Solution Overview

Problem

Current fuel injector shields with copper alloy thermal conductivity do not adequately address the need for enhanced thermal protection and fuel sealing between the nozzle and engine block, as they rely on materials with similar thermal properties and lack effective fuel protection.

Innovation Solution

A shield with a metallic body made of copper alloy and an external thermal protecting member, such as a tin coating, integrated with a fuel protecting member, which includes a collar for compression between engine block and fuel injector shoulders, allowing for improved heat dissipation and fuel containment.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Temperature

If a copper alloy shield is used for heat dissipation, then thermal conductivity is improved, but fuel sealing capability deteriorates

Engineering Contradiction:
Improveheat dissipationVSAvoidfuel sealing
Core Design Contradiction:
TemperatureVSReliability

Solution Approach 1:

The shield is constructed as a composite structure with a copper alloy base material providing thermal conductivity for heat dissipation, and a tin coating layer providing fuel sealing capability. This composite approach allows both functions to coexist without compromise.

Inventive Principle:
Principle #40Composite materials

2Reliability

If a tin coating is applied for fuel protection, then fuel sealing is improved, but thermal conductivity deteriorates

Engineering Contradiction:
Improvefuel sealingVSAvoidheat dissipation
Core Design Contradiction:
ReliabilityVSTemperature

Solution Approach 1:

The shield employs local quality differentiation where the bulk material (copper alloy) provides thermal conductivity for heat dissipation, while the surface layer (tin coating) provides fuel sealing. Each region of the shield has optimized properties for its specific function.

Inventive Principle:
Principle #3Local quality

3Reliability

If the collar is compressed for sealing, then fuel containment is improved, but mechanical stress on the shield increases

Engineering Contradiction:
Improvefuel containmentVSAvoidmechanical stress
Core Design Contradiction:
ReliabilityVSStress or pressure

Solution Approach 1:

The collar acts as an intermediary sealing element that is compressed to provide fuel containment. This mediator absorbs the mechanical stress of compression, protecting the main shield body from excessive stress while maintaining effective sealing.

Inventive Principle:
Principle #24Intermediary (Mediator)

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

The solution effectively reduces heat transfer from the combustion chamber to the nozzle while preventing fuel contact with the copper alloy, enhancing thermal protection and maintaining the injector's position securely.

Implementation Method 1

The thermal protecting member has a lower thermal conductivity than the metallic body

Methodology Applied
Scientific EffectThermal insulation: Thermal Insulation

Implementation Method 2

the shield enables in use to evacuate the heat generated in a combustion chamber and transferred to the nozzle, from said nozzle toward the engine block

Methodology Applied
Scientific EffectThermal conduction: Conduction (thermal)

Data Source

PatentEP3365549B1Fuel injector nozzle shield
Publication Date: 2019.12.11 DELPHI TECH IP LTD
  • EP3365549B1 patent drawingFigure 1

AI summary

A shield (36) is adapted to be arranged between the nozzle (30) of a fuel injector (26) and an engine block (10), the shield (36) having a metallic body comprising a tubular portion (38) inside of which the cylindrical nozzle of the fuel injector can be press-fitted with interference and, that is able to be inserted with clearance (C) in a cylindrical hole of the engine block. The shield (36) further comprises a thermal protecting member (56) arranged over the external face (54) of the tubular portion.